Diagnostic patient monitor

ABSTRACT

A diagnostic patient monitor is provided which monitors the condition of a patient by means of a sensor system to provide output signals, not less than six in number, indicative of normal, above normal or below normal sensed conditions from at least two sensors. The signals are used to directly indicate each condition and are combined so that specific combinations of abnormal signals provide an indication of the condition of the patient resulting in the abnormal signals. Two abnormal signals occurring simultaneously result in the activation of an alarm.

United States Patent [72] Inventor John Stewart Simpson Stewart 50 TheCommon, Parbold, Wigan, Lancashire, England [21] Appl. No. 848,930 [22]Filed Aug. 11, 1969 [45] Patented Nov. 9, 1971 [32] Priority Aug. 9,1968 [33] Great Britain [31 38,245/68 [54] DIAGNOSTIC PATIENT MONITOR 9Claims, 3 Drawing Figs.

[52] US. Cl 128/205 R, 128/206 R, l28/2.1 R [51] Int. Cl A6lb 5/02 [50]Field ofSearch 128/206, 2.1, 2.05 T, 2.05 P, 2.05 S, 2

[56] References Cited UNITED STATES PATENTS 3,135,264 6/1964 Tischler eta1. 128/205 R 3,140,710 7/1964 Glassner et a1. 128/205 S 3,156,23511/1964 Jaeger 128/206 A 3,342,176 9/1967 Kaplan et al.. 128/2.06 R3,513,833 5/1970 Finch et a]. 128/206 R DISCRIMINA TOR CONVERTER DISCRIMINA TON DISCRIMINATOR Nor-- 3,524,442 8/1970 1101111 128/2.06AFOREIGN PATENTS 911,078 11/1962 GreatBritain 128/2.06A

OTHER REFERENCES Body Function Recorder, Honeywell Co. Sales Pamphlet,(12-8-61 (copy in 128/2.1 R)

The Lancet, Oct. 13, 1962, pp. 759- 60, (copy in l28/2.l

Popular Electronics, Nov. 1964, pp. 45- 48, 108- Ill, (copy in l28/2.lR)

Surgery, Dec. 1968, pp. 1057- 1070 (copy in 1.28/2.l R)

Primary Examiner-Richard A. Gaudet Assistant Examiner-- Kyle L. HowellAttorney-Lawrence E. Laubscher ABSTRACT: A diagnostic patient monitor isprovided which monitors the condition of a patient by means of a sensorsystem to provide output signals, not less than six in number,indicative of normal, above normal or below normal sensed conditionsfrom at least two sensors. The signals are used to directly indicateeach condition and are combined so that specific combinations ofabnormal signals provide an indication of the condition of the patientresulting in the abnormal signals. Two abnormal signals occurringsimultaneously result in the activation of an alarm.

WALARM -SENSORS ,MAd/M at POWER DIAGNOSTIC PATIENT MONITOR Thisinvention relates to apparatus for supervising the condition of apatient.

In existing apparatus a measurement is derived from a patient by way ofa sensor. This measurement or another derived from it and called aparameter is obtained continuously. The clinician sets the upper andlower limits of the range which is acceptable as nonnal in the patient.Departures from this range are denoted by alarm signals. Severalparameters may be similarly and simultaneously derived with theirrespective alarm signals. The multiplicity of alarms, many of which aretrivial or false, distresses the patient and destroys the confidence ofthe nursing and medical staff in the accuracy and reliability of theapparatus.

The improved apparatus described herein processes the signals from atleast three parameters. Preferably the three parameters are heartaction, blood circulation and respiration gas exchange. A diagnosis ismade of the condition and of its urgency of need for treatment. Thediagnosis is in respect of clinical condition, sensor performances andpower reserves. This information is communicated in a simple ambiguousway by visual displays and auditory signals. All the important clinicalemergencies which are associated with acute circulatory failure: cardiacarrest, hypoxia and shock, are diagnosed and indicated with accuracy andreliability..The features of which each diagnosis is compounded are alsoindicated.

Many of the alarm systems proposed in the past have suffered from thedisadvantage of providing frequent false alarms. Monitoring systems aremore reliable if multiple parameters are processed and alarms arerestricted to simultaneous transgression of limits in respect to twoparameters or if sensors are duplicated. This is because the weakestlink in the system is the patient sensor interface. It is the purpose ofthe invention to provide an improved monitoring system which representsan optimal solution of the problem from the point of view ofcomprehensiveness and economy.

According to the invention there is provided an apparatus for monitoringthe condition of a patient including at least three input terminals towhich can be applied signals indicating the condition of a patient withrespect to at least three parameters respectively, a circuit arrangementfor deriving signals denotive of the departure of the applied signalsfrom inside a predetermined range and means for providing indicationswhen predetermined combinations of derived signals occur.

Features and advantages of the invention will appear from the followingdescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a block diagram showing an embodiment of the invention;

FIG. 2 illustrates the control panels of an apparatus according to theinvention; and

FIG. 3 is a logic diagram illustrating the operation of the apparatusshown in FIG. 2.

Acute circulatory failure may be due to cardiac insufficiency,peripheral vasodilatation or decreased circulating blood volume,commonly due to cardiac arrest, hypoxia and shock. The three preferredparameters, derived in the example from sensors S1, S2, S3 relaterespectively to heart action, rate, force, volume or efficiency; toblood circulation, pressure, flow, velocity or efficiency and torespiration, in lungs or tissues, rate, for'ce, volume or efficiency.Thus a type S1 sensor measures, for example, heart rate, stroke volumeor ventricular force, etc. Heart rate, for example, may be derived fromelectrocardiogram, phonocardiogram, peripheral pulses or from the waveform of blood pressure, blood flow, blood velocity, etc. A type S2sensor measures, for example, blood pressure, blood flow, blood velocityor circulation time. These may be derived from finger pulse orintra-arterial catheter using strain gauge, pressure transducer,electromagnetic flow meter or ultrasonic velocity meter, etc. A type S3sensor measures, for example, respiration rate, oxygen tension, carbondioxide partial pressure or acidosis. Respiration rate may be derivedfrom respiration sounds, impedance plethysmography, strain gauge, nasaltemperature, etc. Gas levels in blood or tissues may be derived fromoximeter, electrode, electroencephalogram, etc.

The responses of the parameters can be in various forms, but it isconvenient if the responses are translated to digital or analogueequivalents in a common quantity. Electrical variations of voltage orcurrent are especially suitable but other quantities, such as hydraulicor pneumatic pressure, mechanical force or displacement can be used alsobut in general electrical equivalents can be obtained easily, if notproduced directly by the appropriate sensor and once obtained can bereadily processed. In the arrangement described more fully herein thesensors S1, S2 and S3 derive respectively the electrocardiogram heatrate, the blood pressure and the oximeter oxygen tension. Thus the inputof the analyzer, or data processing unit, consists of electricalequivalents of heart action, blood circulation and respiration.

Reliability is obtained by a process of comparison and logic analysisperformed in the analyzer. The sensor output is examined before or afterderivation of the desired parameter to determine if it is characteristicor meaningful. Detachment of a measuring device may be detected in thisway. Each parameter is examined in respect of nature, duration andrapidity of response in addition to simple departure from range. Somefalse signals, for example those due to motion artifact or some truesignals of trivial importance, for example tachycardia due to physicalexertion, are thus prevented from giving alarms. The same parameters,derived by duplication of sensors or otherwise, from different sourcesare examined. Disparity indicates false signals due, for example, toartifact or detachment of a sensor.

Accuracy of diagnosis is achieved by a process of logic analysisperformed in the analyzer or data processing unit. Data presented to theanalyzer can be expressed quantitatively as high H), normal (0), or lowIf a quantitative estimate is made successively for heart rate, bloodpressure and oximetry, a simple three symbol code expresses thesituation. Thus the normal is (0 0 0) and a patient with oligaemic shockwho has tachycardia, hypotension and as yet normal oxygen tension, wouldbe represented as 0). The clinician would be alarmed by or 0) whichwould be found in ventricular fibrillation and would wish to know aboutwarning signs such as tachycardia 0 0), hypertension (0 0) andcyanoisis(0 0 He would also wish to know about 0 0) which would indicatethat the electrocardiogram has been disconnected.

The permutation of three settings 0 with three signals, heart rate,blood pressure, oximetry, are 3 or 27. The clinical meaning which isassigned to each of the permutations is given in the following table.

TABLE Blood Heart rate pressure oximeter Warning Alarm 0 H HX HC 0 L LXA LC A(S) 0 T TXS TC S 0 'IHS 'IHXS THC S 0 TL S TLX (S)A TLC (S)A 0 BBX NOTE: X=Oxizmeter; B=Bradyeardia; V=Ventricular fibrillation oraSystole; C=Cyanosis; A=Anoxia; 'I='Iachycardia; S=Surgical shock;H=High B.P.; L=Low B.P.; =Normal; =Low reading; +=High reading.

It is a main purpose of the machine to communicate with those tendingthe patient if the condition of the patient and the machine is notentirely satisfactory. The output indicates firstly the abnormal state,clinical or machine, secondly the component clinical signs or machinefaults which make up the abnormal state, and thirdly the degree ofurgency of the indicated condition. The output may be visual withcontinuous or flashing lights or illuminated panels indicating thecondition or it may be auditory with continuous or intermittent warningor alarm sounds. Provision can be made for connection to a pacemaker inwhich case a panel light PACER can be illuminated when this is inaction. A light comes on when the power is switched on and there is alsoa series of on/off switches.

In practice, one central unit can be used with numerous patients. Eachpatient is then provided with appropriate sensors and the sensors ofeach patient in turn can be connected to the data processing part of theapparatus.

Additional optional equipment includes the pacemaker already mentioned,an oscilloscope for display of the electrocardiogram, blood pressure oroximeter reading and a recorder for producing permanent records. Itshould be noted that it is not necessary to provide digital display,dials or meters showing the numerical values of the measurements. Ifthese are within the permitted limits no record is necessary; if not, awarning is given and the absence of a dial encourages the nurse to lookat the patient, where her attention should be directed, not at themachine. In the event of an arrest display and recording equipment mightbe helpful but such equipment is portable and can be brought: it neednot be incorporated for it is not an essential part of every monitor.

The form of one embodiment of the apparatus is shown diagrammatically inFIG. 1. Sensors S1, S2 and 53 are applied to a patient; for reasonsmentioned above, the sensors may be duplicated or supplemented. Similarsensors are applied to other patients, the responses being derived overleads P2, etc. The sensor outputs are selected in sequence by selectorswitches SS1, SS2, SS3 and applied to comparator stages Cl, C2, C3, andthe outputs compared against settable standard responses from sourcesRl, R2, R3. If desired, the reference responses may be set for thesensor for each patient, as by reference switches RS1, RS2, RS3, movingwith the selector switches.

The derived error or deviation signals are fed to the data processingunit DPU and caused, on the logic of the Table, to operate visual andauditory warning and alarm indicators W, A respectively. The pacemakerPS sensor controls, through the processing unit DPU, the pacemakerindicator P.

In the embodiment described here (FIG. 2) the display con sists ofilluminated diagnosis panels 61 which give the diagnosis or machinefault and an analysis panel 60 showing the sensor state in a panel ofnine indicator lights which give the component features of clinical andsensor conditions. In the diagnosis panel 61 ABNORMAL is illuminated ifthere is any clinical or sensor abnormality. Diagnosis of ARREST, ANOXIAand SHOCK are illuminated when appropriate according to the logic of theTable. The panels SENSOR and POWER are illuminated in the event ofsensorfault or power failure.

The anaylsis panel indicates the state of each sensor of type 81, S2 andS3, whether normal, high" or low due to clinical condition as in thetable or sensor fault. Adjacent to each high or low indicator light ofthe analysis panel 60 may be given if desired the appropriate clinicalsign or feature, for example, tachycardia, bradycardia, hypertension,hypotension, cyanosis. As noted later, this is dependent to some extenton the type of sensor used.

The type of auditory output, WARNING or ALARM, is also shown in thetable. Controls for the auditory warning 66 permit regulation in respectof volume and of time interval between visual display and auditorywarning. Usually the person tending the patient will note an abnormality(one parameter abnormal; see Table and correct this early warning beforethe auditory warning sounds and without disturbing the patient. It isnoted (see table) that early shock is a warning condition but severeshock is an alarm condition.

Level set controls are provided for each sensor. For the type S] sensor,here the electrocardiogram, the central control 57 is used to set themachine normal" to the patients heart rate. The adjacent maximum 59 andminimum 58 controls set the upper and lower permitted limits. Similarsets of controls for type 52 and type S3 sensors are provided.

The type 81 sensor input is by a socket 51 and adjacent is an outputsocket 52 for display, if desired. Similar sockets are provided by thetype S2 sensor 53, 54 and the type S3 sensor 55, 56.

Also shown are a machine on" indicator light 63, auditory warning volumeand time delay control 66, switches to reset alarm 64 and display 65 andan on/off switch 67. The alarm reset switch 64 is used to suppresstemporarily the auditory alarm when setting up the machine or attendingto a patient after an alarm. It returns automatically to the alert"position after an interval. This display caused by any abnormalcondition is held until reset to normal" by the reset display button 65.

The logic circuit of the apparatus is shown in greater detail in FIG. 3.The sensors are indicated as S1, S2 and S3 at the left-hand side of thedrawing, and as stated above they produce signals generally in analogueform related to heart action, circulation and respiration respectively.In the embodiment described herein they are an ECG, blood pressure meterand oximeter respectively. The signal from the ECG. is applied to theapparatus at the input tenninal and transformed by a circuit indicatedby the block 1 to an analogue signal the value of which depends on pulserate, and applied to a discriminator 2 which has three outputs. Signalsappear on an appropriate output conductor dependent on whether the rateis normal, too high or too low respectively, these conductors beingdesignated 0, and respectively as shown.

In a similar manner signals from a blood pressure meter and oximeter areapplied to circuits 3 and 4 respectively which, like the circuit 2, eachhave three outputs, a signal appearing on the appropriate one of thethree in dependence on whether the value is normal, too high or too low.

Associated with each sensor S1, S2 and S3 there is provided a circuit,30, 31 and 32 respectively, which provides an output signal when nomeaningful signal is being received from the appropriate sensor. Thiscan happen for example if the sensor goes faulty or drops off thepatient. These output lines are designated NIL.

The three NIL conductors are connected to the OR gate 5 which isconnected to the SENSOR indicator so that the SEN- SOR indicator andwarning are operated if any of the sensors fail. Similarly, the NILconductors are connected in pairs to the three OR gates 6, 7 and 8,which are in turn connected to a 3-gate (three input and gate) 9. Theoutput from the 3-gate 9 is connected to an OR gate 10 the output ofwhich is connected to the ALARM indicator so that the ALARM is operatedwhenever two or more of the sensors fail to operate.

The outputs from S2 and S3 are connected to an OR gate 11 the output ofwhich is connected to a 2- gate (two input and gate) 12 the other inputof which is a connection from the output of S1. The output from gate 12is connected to said OR gate and to an OR gate the output of which isconnected to the SHOCK indicator. Thus, both the ALARM and SHOCKindications are given if either low oxygen or low blood pressure areassociated with increased rate of heart beat. Similarly, the outputsfrom S2 and S3 and the output from S1 are connected to OR gate 13 and2-gate (two input and gate) 14 to provide an indication when eitherincreased oxygen or increased blood pressure are associated withincreased rate of heart beat. The output from 2-gate 14 is applied tosaid OR gate 15 so that in these conditions the SHOCK indication isgiven.

The outputs from S2 and S1 are connected to a 2-gate (two input andgate) 16 the output of which is connected to said OR gate 10. The outputof said 2-gate 16 is also connected to the ARREST indicator. Thus, bothALARM and ARREST are indicated when low blood pressure is associatedwith reduced rate of heat beat.

The and lines from S3 are connected to an OR gate 17 the output of whichis connected to a 2-gate (two input AND gate) 18 the other input ofwhich is the output from S2. Thus, gate 18 provides an output whenreduced blood pressure is associated with either increased or reducedoxygen content of the blood. An oximeter is peculiar in that a highreading may be due to disconnection of the sensor from the patient. Insuch a situation an abnormal condition must be assumed. Alternatively,if the original setting is made during cyanosis, a relatively highreading represents return to normality. With other type S3 sensors ahigh reading is abnormal if the original setting was normal. The outputof 18 is connected to said gate 10 to produce an ALARM indication inthese circumstances and also to an indicator ANOXIA.

The NIL conductors from each of the sensors are connected to reversingstages 19, 21 and 23 respectively so as to provide inputs to respective2-gates (two input and gates) 20, 22 and 24 when signals are beingobtained from the sensors S1, S2 and S3. The other inputs of the gates20, 22 and 24 are the respective outputs from said sensors S1, S2 andS3. The outputs from said 2-gates 20, 22 and 24 are applied as inputs toan OR gate 25, to which are also applied signals from the respectivelines from the three sensors. The output from OR gate 25 is applied to agate 26 the other input of which is a signal obtained from the sensorline. The output from said gate 26 is applied to said OR gate 10 so thatan alarm is indicated when there is a failure of one sensor inconjunction with an AB- NORMAL indication from one or more of theremaining sensors. The purpose of circuits 19, in the S1 complex is toinhibit the output in the event of a sensor failure which wouldotherwise give an alarm through circuit 5 and 25. The circuits 2], 22and 23, 24 perform the same functions in the S2 and S3 complexes.

An OR gate 27 has as its inputs connections from each of the and outputsfrom the three sensors so that there is an output whenever any of thesensors indicate an ABNORMAL condition. This is used to indicateABNORMAL and also applied to an OR gate 28 the other input of which is asignal from the SENSOR indication. If either is present, a WARNING isindicated.

The battery is connected via a circuit 29 which provides an output whenno signal is present to an indicator which indicates when there is apower failure. The battery is connected directly to another indicatorwhich indicates when the machine is on.

The 0 and outputs from the three sensors are connected to the controlpanel to indicate in the section designated 60 the nature of the outputsfrom each of the three sensors. It will be seen also that in the sectionof the front panel designated 61 are the indications for the conditionsAB- NORMAL, ANOXIA, ARREST, SHOCK, SENSORS and POWER the operation ofwhich has been described in connection with FIG. 3. An output from theheart beat sensor S1 is applied to the panel to provide a flashingindication of the heart beats of the patient as shown at 62.

It will be appreciated that the nature of the condition which gives riseto a WARNING is dependent to some extent on the nature of the sensorwhich is used. For example, an ear oximeter measures color and diagnosescyanosis, but a respiration rate monitor diagnoses high or low rates,that is, tachypnoea or apnoea and so on. However, providing the threesensors are of the types S1, S2 and S3 as defined above, then the samelogic circuits can be used and all the important ALARM conditions ofANOXIA, ARREST and SHOCK are correctly diagnosed. Moreover, warning ofearly shock is given and also early warning is given if any oneparameter is ABNORMAL.

It will be apparent to those skilled in the art that many changes may bemade to the apparatus described above in accordance with the inventionthus, whilst FIG. 3 illustrates a preferred logical arrangement, it canbe modified by, for example the use of NAND/NOR electronics, fluidlogic, reed or other relays and other types of logic switches.

The analyzer will function correctly with a wide variety of sensorsprovided that one parameter for each group S1, S2, S3, is deriveddirectly or indirectly. It will be apparent to those skilled in the artthat there is a multiplicity of ways for deriving parameters from amultitude of sensors.

These or other sensors may be used to derive other parameters which maybe used to give additional warnings. For example, venous blood pressuremay be used as an index of shock or transfusion requirements; bodytemperature may be used as an index of sepsis or increased intracranialpressure.

What is claimed is:

1. An apparatus for monitoring the condition of a patient and making adiagnosis which includes at least three sensing means for continuouslysensing different physical conditions of said patient, each such sensingmeans operating in response to sensed deviation from a normal conditionto provide one of two abnormal signals, one such abnormal signal beingindicative of an above normal condition and the remaining abnormalsignal being indicative of a below normal condition, a plurality ofcondition indicating means, each such indicating means being operativeto indicate a physical condition resulting in a specific combination ofsaid abnormal signals, diagnostic logic circuit means connected toreceive abnormal signals from said sensing means, said diagnostic logiccircuit means operating upon the simultaneous occurrence of acombination of abnormal signals from at least two of said sensing meansto provide an activating signal to a specific condition indicating meansfor indicating the physical condition giving rise to such combination ofabnormal signals.

2. The apparatus of claim 1 which includes alarm logic:

means connected to receive said abnormal signals, said alarm logic meansoperating upon receipt of at least two simultaneously occurring abnormalsignals to provide an output alarm signal.

3. The apparatus of claim 1 wherein said sensing means operates toprovide a normal signal in response to a sensed normal condition, andsensor monitoring means connected to each such sensing means, saidsensor monitoring means operating to provide a monitor output signal inthe absence of a normal or abnormal signal from an associated sensingmeans, monitor logic means connected to receive monitor output signalsfrom said sensor monitoring means, said monitor logic means operating toprovide a monitor alarm signal in response to the simultaneousoccurrence of two monitor output signals.

4. The apparatus of claim 3 which includes warning logic means connectedto receive said abnormal signals from said sensing means and saidmonitor output signals from said sensor monitoring means, said warninglogic means operating to provide a warning alarm signal upon thesimultaneous occur rence of an abnormal signal and monitor outputsignal.

5. The apparatus of claim 4 which includes alarm means connected tooperate upon receipt thereby of either said monitor alarm signal or saidwarning alarm signal.

6. The apparatus of claim which includes alarm logic means connected toreceive said abnormal signals, said alarm logic means operating uponreceipt of at least two simultaneously occurring abnormal signals toprovide an output alarm signal to operate said alarm means.

7. The apparatus of claim 4 wherein said warning logic means operates toprovide a warning signal upon the occurrence of either an abnormalsignal or a monitor output signal and warning indicator means connectedto to provide a warning indication upon receipt thereby of said warningsignal.

8. The apparatus of claim 1 wherein said sensing means are individuallyresponsive to heart action, circulation and respiration.

9. The apparatus of claim 3 which includes a normal indicator means foreach of said sensing means connected to provide an indication uponreceipt thereby of a normal signal from an associated sensing means, anabove nonnal indicator means for each of said sensing means connected toprovide an indication upon receipt thereby of an above normal signalfrom an associated sensing means and a below normal indicating means foreach of said sensing means connected to provide an indication uponreceipt thereby of a below normal signal from an associated sensingmeans.

4 II R I i

1. An apparatus for monitoring the condition of a patient and making adiagnosis which includes at least three sensing means for continuouslysensing different physical conditions of said patient, each such sensingmeans operating in response to sensed deviation from a normal conditionto provide one of two abnormal signals, one such abnormal signal beingindicative of an above normal condition and the remaining abnormalsignal being indicative of a below normal condition, a plurality ofcondition indicating means, each such indicating means being operativeto indicate a physical condition resulting in a specific combination ofsaid abnormal signals, diagnostic logic circuit means connected toreceive abnormal signals from said sensing means, said diagnostic logiccircuit means operating upon the simultaneous occurrence of acombination of abnormal signals from at least two of said sensing meansto provide an activating signal to a specific condition indicating meansfor indicating the physical condition giving rise to such combination ofabnormal signals.
 2. The apparatus of claim 1 which includes alarm logicmeans connected to receive said abnormal signals, said alarm logic meansoperating upon receipt of at least two simultaneously occurring abnormalsignals to provide an output alarm signal.
 3. The apparatus of claim 1wherein said sensing means operates to provide a normal sigNal inresponse to a sensed normal condition, and sensor monitoring meansconnected to each such sensing means, said sensor monitoring meansoperating to provide a monitor output signal in the absence of a normalor abnormal signal from an associated sensing means, monitor logic meansconnected to receive monitor output signals from said sensor monitoringmeans, said monitor logic means operating to provide a monitor alarmsignal in response to the simultaneous occurrence of two monitor outputsignals.
 4. The apparatus of claim 3 which includes warning logic meansconnected to receive said abnormal signals from said sensing means andsaid monitor output signals from said sensor monitoring means, saidwarning logic means operating to provide a warning alarm signal upon thesimultaneous occurrence of an abnormal signal and monitor output signal.5. The apparatus of claim 4 which includes alarm means connected tooperate upon receipt thereby of either said monitor alarm signal or saidwarning alarm signal.
 6. The apparatus of claim 5 which includes alarmlogic means connected to receive said abnormal signals, said alarm logicmeans operating upon receipt of at least two simultaneously occurringabnormal signals to provide an output alarm signal to operate said alarmmeans.
 7. The apparatus of claim 4 wherein said warning logic meansoperates to provide a warning signal upon the occurrence of either anabnormal signal or a monitor output signal and warning indicator meansconnected to provide a warning indication upon receipt thereby of saidwarning signal.
 8. The apparatus of claim 1 wherein said sensing meansare individually responsive to heart action, circulation andrespiration.
 9. The apparatus of claim 3 which includes a normalindicator means for each of said sensing means connected to provide anindication upon receipt thereby of a normal signal from an associatedsensing means, an above normal indicator means for each of said sensingmeans connected to provide an indication upon receipt thereby of anabove normal signal from an associated sensing means and a below normalindicating means for each of said sensing means connected to provide anindication upon receipt thereby of a below normal signal from anassociated sensing means.